In TestNG, the assertion assertEquals is used to compare the expected and actual values in a test case. It checks if the two values are equal and reports a failure if they are not. Here’s how you can use assertEquals in TestNG:

1. Import the required TestNG assertion class:

2. Use assertEquals in your test method to compare the expected and actual values. The syntax is as follows:

3. Here’s an example test method that uses assertEquals:

In the above example, the assertEquals method compares the actualResult (which is the result of adding 2 and 2) with the expectedResult of 4. If the two values are not equal, a failure will be reported with the provided error message “Addition result mismatch”.

The assertEquals method is overloaded and supports different data types, including primitives, objects, arrays, and more. You can also add an optional error message as the last parameter to provide more context in case of assertion failures.

TestNG provides several other assertion methods like assertTrue, assertFalse, assertNull, assertNotNull, and more, which you can use based on your specific testing needs.

Using assertions in your test methods helps in validating the expected behavior and provides feedback on test failures, enabling you to identify issues and fix them promptly.